Veröffentlicht am

Six Planets from Yosemite

The five naked-eye planets, Mercury, Venus, Mars, Jupiter and Saturn, have been seen since ancient times to wander the night skies of planet Earth. So it could be remarkable that on this night, standing at the side of a clear, calm lake, six planets can be seen with the unaided eye. Have a look. Very bright and easy to spot for skygazers, yellowish Mars is left of a pale Milky Way. Saturn is immersed in the glow of the Milky Way’s diffuse starlight. Jupiter is very near the horizon on the right, shining beyond the trees against the glow of distant city lights. Last weekend, while admiring this night time view across beautiful, high-altitude Lake Tanaya in Yosemite National Park, a thoughtful and reflective observer could probably see three planets more. via NASA https://ift.tt/2JJ38fi

Veröffentlicht am

Shades of Martian Darkness

Science operations for NASA’s Opportunity rover have been temporarily suspended as it waits out a dust storm on Mars. This series of images shows simulated views of a darkening Martian sky blotting out the Sun from NASA’s Opportunity rover’s point of view,. via NASA https://ift.tt/2JVsVo9

Veröffentlicht am

Ramp-Up in Antarctic Ice Loss Speeds Sea Level Rise

Ice losses from Antarctica have tripled since 2012, increasing global sea levels by 0.12 inch (3 millimeters) in that timeframe alone, according to a major new international climate assessment funded by NASA and ESA (European Space Agency).

from NASA https://ift.tt/2JPHDwQ
via IFTTT

Veröffentlicht am

Red Cloudbow over Delaware

What kind of rainbow is this? In this case, no rain was involved — what is pictured is actually a red cloudbow. The unusual sky arc was spotted last month during sunset in Rehoboth Beach, Delaware, USA. When the photographer realized that what he was seeing was extraordinary, he captured it with the only camera available — a cell phone. Clouds are made of water droplets, and in a cloudbow a cloud-droplet group reflects back light from the bright Sun (or Moon) on the opposite side of the sky. Similar phenomena include fogbows and airplane glories. Here, the red color was caused by atmospheric air preferentially scattering away blue light — which simultaneously makes most of the sky appear blue. A careful inspection reveals a supernumery bow just inside the outermost arc, a bow caused by quantum diffraction. via NASA https://ift.tt/2JwjLPn

Veröffentlicht am

NASA Flies Large Unmanned Aircraft in Public Airspace Without Chase Plane for First Time

NASA’s remotely-piloted Ikhana aircraft, based at the agency’s Armstrong Flight Research Center in Edwards, California, successfully flew its first mission in the National Airspace System without a safety chase aircraft on Tuesday. This historic flight moves the United States one step closer to normalizing unmanned aircraft operations in the airspa

from NASA https://ift.tt/2LMNOPh
via IFTTT

Veröffentlicht am

Evaluating the Noise of Future Aircraft

To address the expected noise levels of future aircraft, NASA’s Commercial Supersonic Technology project is already developing technologies focused on reducing the noise produced by an aircraft’s engine exhaust. via NASA https://ift.tt/2sQ9PG6

Veröffentlicht am

Star Size Comparison 2

How big is our Sun compared to other stars? In dramatic and popular videos featured on YouTube, the relative sizes of planets, stars, and even the universe are shown from smallest to largest. The featured video begins with Earth’s Moon and progresses through increasingly larger moons and planets in our Solar System. Soon, the Sun is shown and compared to many of the brighter stars in our neighborhood of the Milky Way Galaxy. Finally, star sizes are shown in comparison with the Milky Way Galaxy, galaxies across the observable universe, and speculatively, regions of a potentially greater multiverse. Note that the true sizes of most stars outside of the Sun and Betelgeuse are not known by direct observation, but rather inferred by measurements of their perceived brightness, temperature, and distance. Although an inspiring learning tool that is mostly accurate, APOD readers are encouraged to complete the learning experience — and possibly help make future versions more accurate — by pointing out slight inaccuracies in the video. via NASA https://ift.tt/2y5NR70